Applicant's invention is an improvement upon U.S. Pat. Des. No. 245,754. The hacksaw shown in that patent uses a bolt (having a wing-like bolt head) that is engaged to a nut which freely floats within the hollow handle. When the bolt head is turned by the user, it causes a rocker arm to pivot which pulls on the rear of the blade to increase blade pressure. This arrangement requires considerable force to be applied to the bolt head by the user, sometimes causes the threads on the bolt to strip, and occasionally results in the loss of the nut out of the top of the hollow handle when the bolt is backed off too far.
This invention is also an improvement on the hacksaw shown in U.S. Pat. No. 1,078,599. That patent shows a hacksaw which has a pivoted lever which cams a separate sliding pin against the head of a bolt to pivot a rocker arm to increase blade tension.
These two prior art patents constitute the closest prior art known to applicant.